The invention relates to a method of processing sheet-like workpieces in a strip-shaped manner, the material sheet being worked in a strip-shaped manner in working steps by means of a controlled linear unit and always in the same X-axis direction.
German Patent 508 474 discloses a method of producing parallel cut or hole rows one after the other in blank material sheets. The material sheet, with the one longitudinal edge which runs parallel to the feed direction being placed against a stop strip, is first of all provided with a first cut row, is then removed completely from the region of the press and, for the purpose of producing the second and the following cut rows, in each case after being displaced in the sheet transverse direction, is fed again to the tool and always in the same feed direction. For producing the respectively second, third and following cut rows in the material sheet, the spacing of the rows is effected by placing the one original sheet longitudinal edge against a stop strip which can be adjusted at the same time in each case, so that finally the entire original material sheet is pierced with cut or hole rows in the manner described above and can be discarded.
On the other hand, however, it is also possible,when each row is stamped or cut out, for the scrap (stamped grid) which is being produced or has been produced to be cut off from the original or the previous longitudinal edge at a distance corresponding to the spacing of the rows. In this way, the original material sheet, each time the stamped-grid strip is dispensed with, is reduced down to the last strip, which is then discarded after the stamping of the hole rows.
This prior art has the disadvantage that in each case only a single material sheet is worked in cut rows, the material sheet already provided with a cut row being taken completely out of the region of the press in each case and passing via a relatively large distance behind the press in the same feed direction again into the region of the-cutting tool, with the result that considerable time is needed for working a material sheet.
Furthermore, PCT/SE 93/00820-WO 94/08740 discloses a method and an apparatus for processing sheets on C-frame presses, this apparatus progressively working a material sheet in a strip-shaped manner in the X-direction in a horizontal processing plane. After a strip has been progressively processed from the metal sheet and subdivided into sections, the respectively remaining residual grid is in each case subsequently separated and removed section by section. After this, the remaining residual sheet is returned at the level of the bottom tool position above the table fixed to the frame into the initial position, is displaced transversely to the processing direction by one strip width, and is progressively processed again in the X-direction.
This type of sheet processing enables a single metal sheet to be worked in a strip-shaped manner in steps from the selected first feed side in each case, so that, as a result of the return, larger time intervals inevitably occur in each case in which no cut parts are produced. A high discharge sequence of workpieces cannot be achieved by means of this method either.
The object of the invention, then, is to propose a method of processing sheet-like workpieces in a strip-shaped manner for high working frequencies.
According to the invention, this object is achieved in terms of the method by the features of patent claim 1.
In this case, the processing method is based on the fact that at least two material sheets are always alternately and cyclically processed in a strip-shaped manner in working steps and always in the same X-axis direction. In this case, a first material sheet is worked cyclically in a strip-shaped manner in the X-axis direction at its bottom side end, and a further material sheet follows the first material sheet in the same X-axis direction. After the last processing step on the strip, being processed, of the first material sheet has been effected, the respectively bottom side is directly worked from a second material sheet in a strip-shaped manner in the same X-axis direction.
The first material sheet, reduced by one material strip, is now returned directly at the processing space against the X-axis feed direction into the initial position and is corrected in the Y-axis direction in the strip depth to be worked. This first material sheet, which has thus been returned, will now in turn directly follow the last working step of the second material sheet, a further strip-shaped part being worked cyclically from this first material sheet. This processing of strip-shaped parts of material sheets in always the same X-axis direction is continued until one material sheet has only a last strip-shaped material-sheet part, which, as described according to the invention, is processed cyclically. A new material sheet then follows this respectively last strip-shaped material-sheet part of each cyclically worked material sheet, and this new material sheet then follows the material sheet, still being processed, in the X-axis processing direction.
Thus it is possible for the first time to cyclically work material sheets in a strip-shaped manner in always the same X-axis direction at high working frequencies without time losses.
The material sheet prepared for the sheet processing, before a strip is worked cyclically, is advantageously moved laterally into the processing plane, is processed, and is moved out of the processing plane again after the separation of the residual grid.
A further design of the invention is seen in the fact that the material sheets to be worked cyclically, including the last strip-shaped part of a material sheet, are in each case returned laterally outside the processing plane against the X-axis direction of the processing into the respective ready position.
In an especially advantageous manner, the invention is characterized in that directly following the strip-shaped end of each material sheet, including the last strip end of a material sheet, in a cyclical manner is in each case a start of the following material sheet, including the strip-shaped start of a worked material sheet.